Annual fixed cost adjustment mechanism deferral amount, whether approved or requested.

No definition available.

Name:	ida_Annualfixedcostadjustmentmechanismdeferral
Namespace Prefix:	ida_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

REGULATORY MATTERS: Idaho Fixed Cost Adjustment (Details) - USD ($) $ in Millions	Jun. 01, 2019	Jun. 01, 2018	Jun. 01, 2017
Idaho Fixed Cost Adjustment [Line Items]
Annual fixed cost adjustment mechanism deferral	$ 34.8	$ 15.6	$ 35.0
Idaho fixed cost adjustment mechanism
Idaho Fixed Cost Adjustment [Line Items]
Percentage cap on the FCA adjustment	3.00%